I. Field of the Disclosure
The technology of the disclosure relates generally to integrated circuits, and particularly to diplexer designs in an integrated circuit.
II. Background
The wireless communication industry continues to work towards providing as much bandwidth to consumers as possible. To this end, many wireless carriers have adopted carrier aggregation policies for current generation communications. That is, a wireless carrier such as AT&T® may own rights to two frequency bands (e.g., 700 MHz and 2 GHz) in a particular geographic area. To maximize available bandwidth, the wireless carrier may use both frequencies simultaneously for a single communication stream. While this does increase the amount of data that can be provided to the end user, there are complications in that each of the frequencies used to transmit data creates noise at the harmonic frequencies. In the AT&T example, the 700 MHz transmissions create harmonics at 2.1 GHz which may interfere with data being broadcast at the 2 GHz frequencies. In such situations, a diplexer can help process signals carried in a carrier aggregation system. In a chipset for a device using such a carrier aggregation system, the diplexer is usually inserted between an antenna and a tuner (or a radio frequency (RF) switch) to ensure high performance. Usually, a diplexer design includes inductors and capacitors. Diplexers can attain high performance by using inductors and capacitors that have a high quality (Q) factor. High performance diplexers can also be attained by reducing the electromagnetic coupling between components, which may be achieved through an arrangement of the geometry and direction of the components. Diplexer performance may be quantified, by measuring the insertion loss and rejection (e.g., quantities expressed in decibels (dB)) at certain frequencies.
Fabricating high performance diplexers in an efficient and cost-effective manner is problematic as the materials required to achieve the high Q may not lend themselves to easy manufacturing processes. Reducing the electromagnetic coupling between the various components in the diplexer, while decreasing the size of the diplexer and making the most economical use of resources, would be beneficial.
The previously incorporated related application provides several ways to make diplexers suitable for a single wireless carrier. However, wireless device manufacturers may desire to make wireless devices that work with multiple carriers. Unfortunately, the wireless carriers do not operate at the same frequency bands and a diplexer optimized to work with one set of frequency bands may be unsuitable for a different set of frequency bands. Thus, there needs to be a way to allow a transceiver to work with multiple frequency bands for multiple carrier aggregation schemes.